What is HPV?
The Centre for Health Protection describes human papillomavirus as a group of more than 150 virus types, about forty of which infect the human genital organs.
Some HPV types cause pre-cancerous change and cancer of the cervix, vagina, vulva and anus. Not every type carries that risk, which is where the distinction between high-risk and low-risk types comes from — and why the vaccines are named by how many types they cover.
Which HPV types cause cancer?
The Centre for Health Protection states that about 90 per cent of cervical cancers in Hong Kong are caused by HPV types 16, 18, 31, 33, 45, 52 and 58, and that the nine-valent vaccine covers those seven genotypes.
Worth noticing is that this set of types is a Hong Kong figure rather than a universal list. The distribution of circulating HPV types differs between places, so “covers 90 per cent of cervical cancers here” is a statement with a geographic premise that overseas material may not share.
| Item | Figure | What it means |
|---|---|---|
| HPV types in total | More than 150 | About 40 of them infect the genital organs |
| Cancer-causing types here | 16, 18, 31, 33, 45, 52, 58 | Behind about 90% of cervical cancers in Hong Kong |
| Nine-valent vaccine coverage | All seven of the above | High coverage, though not every type |